We extend a standard model of parental investment and intergenerational mobility to include a fully specified genetic analysis of skill transmission. The model’s predictions differ substantially from the standard model’s. The coefficient of intergenerational income elasticity (IGE) may be larger than that in the standard model and depends on the distribution of the genotype. The distribution of genetic endowments may be stratified according to income. The model is tested on data, including genetic information, of twins and their parents, estimating how IGE is affected by genetic factors and how environment and genes interact. The effect of intelligence is substantially stronger than that of other traits.